py3: fix handling of ctrl keys in crecord (issue6213) The "keypressed" value in handlekeypressed() is a key name obtained by curses's getkey(); this can be a multibyte string for special keys like CTRL keys. Calling curses.unctrl() with such a value fails on Python 3 with a TypeError as described in issue6213. (On Python 2, this does not crash, but I'm not sure the result is correct, though it does no matter here.) So instead of calling unctrl(), we compare "keypressed" with the expected "^L" obtained by curses.ascii.ctrl("L").